ATtiny88 Automotive Atmel Corporation, ATtiny88 Automotive Datasheet - Page 28

• Manufacturer Part Number: ATtiny88 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATtiny88 Automotive

• Flash (kbytes): 8 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 28
• Ext Interrupts: 28
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 64
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 125
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

6.3
28
Calibrated Internal Oscillator
ATtiny88 Automotive
Table 6-2.
The main purpose of the delay is to keep the AVR in reset until it is supplied with minimum V
The delay will not monitor the actual voltage and it will be required to select a delay longer than
the V
should be used. A BOD circuit will ensure sufficient V
time-out delay can be disabled. Disabling the time-out delay without utilizing a Brown-Out Detec-
tion circuit is not recommended.
The oscillator is required to oscillate for a minimum number of cycles before the clock is consid-
ered stable. An internal ripple counter monitors the oscillator output clock, and keeps the internal
reset active for a given number of clock cycles. The reset is then released and the device will
start to execute.
The start-up sequence for the clock includes both the time-out delay and the start-up time when
the device starts up from reset. When starting up from Power-down mode, V
at a sufficient level and only the start-up time is included.
By default, the Internal Oscillator provides an approximate 8.0 MHz clock. Though voltage and
temperature dependent, this clock can be very accurately calibrated by the user. See
on page 210
“System Clock Prescaler” on page 31
This clock may be selected as the system clock by programming the CKSEL Fuses as shown in
Table
the pre-programmed calibration value into the OSCCAL Register and thereby automatically cal-
ibrates the oscillator. The accuracy of this calibration is shown as Factory calibration in
21-1 on page
By changing the OSCCAL register from SW, see
page
The accuracy of this calibration is shown as User calibration in
When this oscillator is used as the chip clock, the Watchdog oscillator will still be used for the
Watchdog Timer and for the Reset Time-out. For more information on the pre-programmed cali-
bration value, see the section
CKSEL1:0
CC
32, it is possible to get a higher calibration accuracy than by using the factory calibration.
6-3. If selected, it will operate with no external components. During reset, hardware loads
00
10
11
01
rise time. If this is not possible, an internal or external Brown-Out Detection circuit
for more details. The device is shipped with the CKDIV8 Fuse programmed. See
210.
Length of Startup Sequence.
SUT1:0
XX
00
01
10
11
“Calibration Byte” on page
for more details.
Number of WDT Cycles
4K (4,096)
8K (8,192)
“OSCCAL – Oscillator Calibration Register” on
Reserved
Reserved
0
CC
193.
before it releases the reset, and the
Table 21-1 on page
Typical Time-out
CC
Reserved
Reserved
is assumed to be
64 ms
0 ms
4 ms
9157B–AVR–01/10
210.
Table 21-1
Table
CC
.